Trimming vs case length

[BigGame]

My cases don’t seem to stretch. At least nowhere near a trimming length. Many of my cases are below the minimum length. I understand many will trim and chamfer cases regularly to maintain a consistent set. Seems prudent. But if I did that I’d whittle away the cases to nothing.

Do you trim when they’re not long? How short is too short? If weighing short cases vs consistent trim, where do you come out?

Case in mind is 6CM, but question is general.

 

[M-61]

My cases don’t seem to stretch

But if I did that I’d whittle away the cases to nothing

May have lost you here but if the cases do not stretch, what are you whittling?
If you trimmed to one size and they don't stretch....well?

 

[itchyTF]

May have lost you here but if the cases do not stretch, what are you whittling?
If you trimmed to one size and they don't stretch....well?

That’s what I was thinking.

 

[BigGame]

Good point. I do begin to see variability in lengths, but if I were to constantly bring them back to a common length they would be uniformly short. I’m wondering what others do when balancing length vs uniformity and how short is too short.

 

[caihlen]

What cases? What load? What brass? Like to know more about the specifics.

 

[243winxb]

6MM Creedmoor-

The maximum trim length is 1.920" No trimming needed till brass gets longer.
Always measure after full length sizing.

SAAMI 6mm Creedmoor minimum trim length is 1.900"

The longer the brass, the better. Try to maintain 1.920" It will grow , soon or later.

 

[NorCalMikie]

Better yet, measure YOUR chamber, write that spec down and refer to it before you even consider/think about trimming. Chambers are usually cut about .020 longer that Max trim length. Don't fix it if it ain't broke!!

 

[Tokay444]

May have lost you here but if the cases do not stretch, what are you whittling?
If you trimmed to one size and they don't stretch....well?

If his cases don’t grow, in order to trim, he’s got to shorten them every time. Eventually there will be no case.

 

[zipollini]

After full length sizing and neck expanding with a mandrel I ALWAYS run my 6XC cases thru my Giraud trimmer and they always need trimming and chamfering.

 

[M-61]

If his cases don’t grow, in order to trim

My point. WHY and what is he trimming? You trim when the case has 'grown' (Stretched)
Or trim to even a batch out. Not as a requirement each time you reload (might want to wonder where that brass is coming from)
Different cartridge I know but my 222 was trimmed once to even them and never trimmed again. Not sure but that's more than 25+ reloads on them.
My point again, is this is not a STEP. It is a procedure that is done IF necessary.

 

[Tokay444]

My point. WHY and what is he trimming? You trim when the case has 'grown' (Stretched)
Or trim to even a batch out. Not as a requirement each time you reload (might want to wonder where that brass is coming from)
Different cartridge I know but my 222 was trimmed once to even them and never trimmed again. Not sure but that's more than 25+ reloads on them.
My point again, is this is not a STEP. It is a procedure that is done IF necessary.

That’s HIS question.

 

[D-4297]

No . There is no need to trim cases that are already to short . Below OAL base measurement . I have over 100 cases that came with my rifle that were trimmed .015 below minimum OAL by the previous owner . Why ? Who knows why he did it . Lapua cases don't come .015 short from the factory . They are currently on their 14th or 15th reload and haven't been trimmed yet . And they still haven't reached 2.005 for the .308 case OAL . If you're annealing and Bumping .001 / .002 and they aren't growing in length beyond your standard book length OAL , there is nothing to trim . Monitor the situation , and worry about trimming when they grow to .005 / .010 beyond the standard length .

 

[KY_Windage]

I FL-size because that is how I set my shoulders back to about .003 shy of bolt close resistance. I then measure neck-length with a Wilson Case Guage and trim to that. I shoot multiple calibers from .204 up in Hornady and Norma brass (mainly, but some others, too) and not a single caliber fails to stretch and need trimming if, like me, you want them to be the the same OAL every time. Maybe that does not matter in your scheme.

The only cases I have that do not stretch are the ones loaded with drastically reduced powder loads for shooting cast lead bullets.

 

[RegionRat]

All the above plus a few comments.

When I used to play with using commercial and surplus LC for 30-06 Silhouette loads (70-80's), I could struggle with some batches and had easier times with others in terms of neck prep.

The Improved designs versus the standard shoulders created some differences in terms of trim or donut formations, and I used to think that the chamber neck diameter played a role but it turned out that wasn't the key. In terms of the frequency of trimming once the shoulder bump was kept to an absolute minimum, there were times when using a Lee Collet die and Redding Body die, that didn't need a second trim for nearly 10 cycles.

The thing about how the brass tries to flow forward is fun to watch. I didn't enjoy trimming or chamfering very much, so I was always interested in what caused those times when trimming was rarely required versus the ones that were every cycle. The story was complex.

 

[ronemus]

It all depends on your needs. If this is for hunting or plinking at 500 yards or less, don't worry about it - you'll never see any effect due to variations in neck length. If you're shooting benchrest/F-Class/PRS/long range varminting/etc. you need to pay attention to all the details to get consistent high precision - neck length is only one factor among many and definitely not the most important.

 

[Fairchaser]

My cases get trimmed to the same length every time. After they are sized they have grown by the amount of the bump or near that. I use wet tumbling with steel pins so the mouths are peened and require refreshing. The only thing I run into is thinning necks which require a smaller bushing to maintain the same neck tension. I would think that the brass would have to grow some if there is any shoulder bump and I want consistent neck surface holding the bullet.

 

[ronemus]

I trim my cases every time because with a good trimmer (Gracey/Giraud/WFT/etc.) gauging takes longer than trimming, and the trimmer also chamfers inside and outside at the same time. I load in volume, so I'm always looking for ways to be more efficient.

 

[NorCalMikie]

Dies make a big difference. Precision Bushing Bump Dies keep the OAL from growing so not much trimming needed. 20 to 25 resizes with no trimming needed? Works for me.

 

[rjtfroggy]

I reload my cases at least 25 times with no annealing and very seldom a trimming. That equates to about 2 years worth of practice and matches, after that I replace the brass, much cheaper than buying an annealer.
I have yet to have a case grow to much to have to worry about trimming and if they do grow a little I make a pass through the trim die and run a file over them, quick and easy and they all stay the same length.

 

[SSL]

I trim my cases every time because with a good trimmer (Gracey/Giraud/WFT/etc.) gauging takes longer than trimming, and the trimmer also chamfers inside and outside at the same time. I load in volume, so I'm always looking for ways to be more efficient.

Same here. I don't compete, so I don't use the more expensive trimmers, but I size and trim new brass and then just run them through the trimmer after each fire/size cycle as part of my process. If they cut, fine, they needed trimming. If they don't cut, they didn't need it. Doesn't take but a few seconds per case, so not a big deal. I use a Lee Trimmer set (the one with the press mounted die for each cartridge and a power trimmer). Surprisingly consistent and chamfers the case at the same time.